System and method for caching data

ABSTRACT

A method, computer program product, and computing system for processing a read request for a piece of content stored within a storage system. If it is determined that the piece of content is not present within a front end cache system of the storage system, requesting the piece of content from a multi-tiered data array, thus defining requested content. The requested content is received from the multi-tiered data array. A tier designator, concerning the requested content, is received that identifies a specific data tier within the multi-tiered data array from which the requested content was obtained.

TECHNICAL FIELD

This disclosure relates to storage devices and, more particularly, tomulti-tier storage devices.

BACKGROUND

Storing and safeguarding electronic content is of paramount importancein modern business. Accordingly, various systems may be employed toprotect such electronic content. Data storage system are oftencompartmentalized into different tiers having different levels ofperformance, wherein data that is accessed less often is placed into aslower performance tier, while data that is accessed more often isplaced into a higher performance tier.

SUMMARY OF DISCLOSURE

In a first implementation, a computer-implemented method includesprocessing a read request for a piece of content stored within a storagesystem. If it is determined that the piece of content is not presentwithin a front end cache system of the storage system, requesting thepiece of content from a multi-tiered data array, thus defining requestedcontent. The requested content is received from the multi-tiered dataarray. A tier designator, concerning the requested content, is receivedthat identifies a specific data tier within the multi-tiered data arrayfrom which the requested content was obtained.

One or more of the following features may be included. The tierdesignator may be processed to determine whether the requested contentshould be written to the front end cache system. The requested contentmay be written to the front end cache system when the requested contentis obtained from slower data tiers within the multi-tiered data array.The requested content may not be written to the front end cache systemwhen the requested content is obtained from faster data tiers within themulti-tiered data array. The multi-tiered data array may include afaster data tier, a medium data tier, and a slower data tier. The fasterdata tier may include one or more flash storage devices, the medium datatier may include one or more fiber channel storage devices, and theslower data tier may include one or more SATA storage devices. The frontend cache system may be a flash-based front end cache system. Themulti-tiered data array may include a back end cache system.

In another implementation, a computer program product residing on acomputer readable medium having a plurality of instructions storedthereon which, when executed by a processor, cause the processor toperform operations including processing a read request for a piece ofcontent stored within a storage system. If it is determined that thepiece of content is not present within a front end cache system of thestorage system, requesting the piece of content from a multi-tiered dataarray, thus defining requested content. The requested content isreceived from the multi-tiered data array. A tier designator, concerningthe requested content, is received that identifies a specific data tierwithin the multi-tiered data array from which the requested content wasobtained.

One or more of the following features may be included. The tierdesignator may be processed to determine whether the requested contentshould be written to the front end cache system. The requested contentmay be written to the front end cache system when the requested contentis obtained from slower data tiers within the multi-tiered data array.The requested content may not be written to the front end cache systemwhen the requested content is obtained from faster data tiers within themulti-tiered data array. The multi-tiered data array may include afaster data tier, a medium data tier, and a slower data tier. The fasterdata tier may include one or more flash storage devices, the medium datatier may include one or more fiber channel storage devices, and theslower data tier may include one or more SATA storage devices. The frontend cache system may be a flash-based front end cache system. Themulti-tiered data array may include a back end cache system.

In another implementation, a computing system including at least oneprocessor and at least one memory architecture coupled with the at leastone processor, wherein the computing system is configured to performoperations including processing a read request for a piece of contentstored within a storage system. If it is determined that the piece ofcontent is not present within a front end cache system of the storagesystem, requesting the piece of content from a multi-tiered data array,thus defining requested content. The requested content is received fromthe multi-tiered data array. A tier designator, concerning the requestedcontent, is received that identifies a specific data tier within themulti-tiered data array from which the requested content was obtained.

One or more of the following features may be included. The tierdesignator may be processed to determine whether the requested contentshould be written to the front end cache system. The requested contentmay be written to the front end cache system when the requested contentis obtained from slower data tiers within the multi-tiered data array.The requested content may not be written to the front end cache systemwhen the requested content is obtained from faster data tiers within themulti-tiered data array. The multi-tiered data array may include afaster data tier, a medium data tier, and a slower data tier. The fasterdata tier may include one or more flash storage devices, the medium datatier may include one or more fiber channel storage devices, and theslower data tier may include one or more SATA storage devices. The frontend cache system may be a flash-based front end cache system. Themulti-tiered data array may include a back end cache system.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features andadvantages will become apparent from the description, the drawings, andthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a storage system and a data cachingprocess coupled to a distributed computing network;

FIG. 2 is a diagrammatic view of the storage system of FIG. 1; and

FIG. 3 is a flow chart of the data caching process of FIG. 1.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

System Overview:

Referring to FIG. 1, there is shown data caching process 10 that mayreside on and may be executed by storage system 12, which may beconnected to network 14 (e.g., the Internet or a local area network).Examples of storage system 12 may include, but are not limited to: aNetwork Attached Storage (NAS) system, a Storage Area Network (SAN), apersonal computer with a memory system, a server computer with a memorysystem, and a cloud-based device with a memory system.

As is known in the art, a SAN may include one or more of a personalcomputer, a server computer, a series of server computers, a minicomputer, a mainframe computer, a RAID device and a NAS system. Thevarious components of storage system 12 may execute one or moreoperating systems, examples of which may include but are not limited to:Microsoft Windows XP Server™; Novell Netware™; Redhat Linux™, Unix, or acustom operating system, for example.

The instruction sets and subroutines of data caching process 10, whichmay be stored on storage device 16 included within storage system 12,may be executed by one or more processors (not shown) and one or morememory architectures (not shown) included within storage system 12.Storage device 16 may include but is not limited to: a hard disk drive;a tape drive; an optical drive; a RAID device; a random access memory(RAM); a read-only memory (ROM); and all forms of flash memory storagedevices.

Network 14 may be connected to one or more secondary networks (e.g.,network 18), examples of which may include but are not limited to: alocal area network; a wide area network; or an intranet, for example.

Various data requests (e.g. data request 20) may be sent from clientapplications 22, 24, 26, 28 to storage system 12. Examples of datarequest 20 may include but are not limited to data write requests (i.e.a request that content be written to storage system 12) and data readrequests (i.e. a request that content be read from storage system 12).

The instruction sets and subroutines of client applications 22, 24, 26,28, which may be stored on storage devices 30, 32, 34, 36 (respectively)coupled to client electronic devices 38, 40, 42, 44 (respectively), maybe executed by one or more processors (not shown) and one or more memoryarchitectures (not shown) incorporated into client electronic devices38, 40, 42, 44 (respectively). Storage devices 30, 32, 34, 36 mayinclude but are not limited to: hard disk drives; tape drives; opticaldrives; RAID devices; random access memories (RAM); read-only memories(ROM), and all forms of flash memory storage devices. Examples of clientelectronic devices 38, 40, 42, 44 may include, but are not limited to,personal computer 38, laptop computer 40, personal digital assistant 42,notebook computer 44, a server (not shown), a data-enabled, cellulartelephone (not shown), and a dedicated network device (not shown).

Client electronic devices 38, 40, 42, 44 may each execute an operatingsystem, examples of which may include but are not limited to MicrosoftWindows™, Microsoft Windows CE™, Redhat Linux™, or a custom operatingsystem.

Users 46, 48, 50, 52 may access storage system 12 directly throughnetwork 14 or through secondary network 18. Further, storage system 12may be connected to network 14 through secondary network 18, asillustrated with link line 54.

The various client electronic devices may be directly or indirectlycoupled to network 14 (or network 18). For example, personal computer 38is shown directly coupled to network 14 via a hardwired networkconnection. Further, notebook computer 44 is shown directly coupled tonetwork 18 via a hardwired network connection. Laptop computer 40 isshown wirelessly coupled to network 14 via wireless communicationchannel 56 established between laptop computer 40 and wireless accesspoint (i.e., WAP) 58, which is shown directly coupled to network 14. WAP58 may be, for example, an IEEE 802.11a, 802.11b, 802.11g, 802.11n,Wi-Fi, and/or Bluetooth device that is capable of establishing wirelesscommunication channel 56 between laptop computer 40 and WAP 58. Personaldigital assistant 42 is shown wirelessly coupled to network 14 viawireless communication channel 60 established between personal digitalassistant 42 and cellular network/bridge 62, which is shown directlycoupled to network 14.

For the following discussion, client application 22 is going to bedescribed for illustrative purposes. However, this is not intended to bea limitation of this disclosure, as other client applications (e.g.,client applications 24, 26, 28) may be equally utilized.

For illustrative purposes, storage system 12 will be described as beinga network-based storage system that includes a plurality of rotating,electro-mechanical backend storage devices. However, this is forillustrative purposes only and is not intended to be a limitation ofthis disclosure, as other configurations are possible and are consideredto be within the scope of this disclosure. For example and as discussedabove, storage system 12 may be a personal computer that includes asingle electro-mechanical storage device.

Referring also to FIG. 2, storage system 12 may include a servercomputer/controller (e.g. server computer/controller 100), and aplurality of data tiers T 1-n (e.g. data tiers 102, 104, 106). Datatiers 102, 104, 106 may be configured to provide various levels ofperformance. For example. one or more of data tiers 102, 104, 106 may beconfigured to be a lower performance data tier and one or more of datatiers 102, 104, 106 may be configured to be a higher performance datatier.

For example, data tier 102 may be configured as a higher performancedata tier and may include one or more flash storage devices. Data tier104 may be configured as a medium performance data tier and may includeone or more fiber channel storage devices. And data tier 106 may beconfigured as a lower performance data tier and may include one or morelower performance storage devices (e.g., SATA drives, SCSI drives, SASdrives, IDE drives, and EIDE drives).

One or more of data tiers 102, 104, 106 may be configured to providevarious levels of performance and/or high availability. For example, oneor more of data tiers 102, 104, 106 may be configured as a RAID 0 array,in which data is striped across multiple drives. By striping data acrossmultiple drives, improved performance may be realized. However, RAID 0arrays do not provide a level of high availability. Accordingly, one ormore of data tiers 102, 104, 106 may be configured as a RAID 1 array, inwhich data is mirrored between multiple drives. By mirroring databetween multiple drives, a level of high availability is achieved asmultiple copies of the data are stored within storage system 12.

While data tiers 102, 104, 106 are discussed above as possibly beingconfigured in a RAID 0 or RAID 1 array, this is for illustrativepurposes only and is not intended to be a limitation of this disclosure,as other configurations are possible. For example, data tiers 102, 104,106 may be configured in a non-RAID fashion or as a RAID 3, RAID 4, RAID5 or RAID 6 array.

While in this particular example, storage system 12 is shown to includethree data tiers (e.g. data tiers 102, 104, 106), this is forillustrative purposes only and is not intended to be a limitation ofthis disclosure. Specifically, the actual number of data tiers may beincreased or decreased depending upon system needs.

As discussed above, data tiers 102, 104, 106 may include one or more oneor more flash storage devices, fiber channel storage devices, and lowerperformance storage devices (e.g., SATA drives, SCSI drives, SAS drives,IDE drives, and EIDE drives).

Storage system 12 may execute all or a portion of data caching process10. The instruction sets and subroutines of data caching process 10,which may be stored on a storage device (e.g., storage device 16)coupled to server computer/controller 100, may be executed by one ormore processors (not shown) and one or more memory architectures (notshown) included within server computer/controller 100. Storage device 16may include but is not limited to: a hard disk drive; a tape drive; anoptical drive; a RAID device; a random access memory (RAM); a read-onlymemory (ROM); and all forms of flash memory storage devices.

As discussed above, various data requests (e.g. data request 20) may begenerated. For example, these data requests may be sent from clientapplications 22, 24, 26, 28 to storage system 12.Additionally/alternatively and when server computer/controller 100 isconfigured as an application server, these data requests may beinternally generated within server computer/controller 100. Examples ofdata request 20 may include but are not limited to data write request108 (i.e. a request that content 110 be written to storage system 12)and data read request 112 (i.e. a request that content 110 be read fromstorage system 12).

Server computer/controller 100 may include input-output logic 114 (e.g.,a network interface card or a Host Bus Adaptor (HBA)), processing logic116, and first cache system 118. Examples of first cache system 118 mayinclude but are not limited to a volatile, solid-state, cache memorysystem (e.g., a dynamic RAM cache memory system) and/or a non-volatile,solid-state, cache memory system (e.g., a flash-based, cache memorysystem).

During operation of server computer/controller 100, content 110 to bewritten to storage system 12 may be received by input-output logic 114(e.g. from network 14 and/or network 18) and processed by processinglogic 116. Additionally/alternatively and when servercomputer/controller 100 is configured as an application server, content110 to be written to storage system 12 may be internally generated byserver computer/controller 100. As will be discussed below in greaterdetail, processing logic 116 may initially store content 110 withinfirst cache system 118.

Depending on the manner in which first cache system 118 is configured,processing logic 116 may immediately write content 110 to second cachesystem 120/data tiers 102, 104, 106 (if first cache system 118 isconfigured as a write-through cache) or may subsequently write content110 to second cache system 120/data tiers 102, 104, 106 (if first cachesystem 118 is configured as a write-back cache). Examples of secondcache system 120 (i.e., a backend cache system) may include but are notlimited to a volatile, solid-state, cache memory system (e.g., a dynamicRAM cache memory system) and/or a non-volatile, solid-state, cachememory system (e.g., a flash-based, cache memory system).

The combination of second cache system 120 and data tiers 102, 104, 106may form data array 122, wherein first cache system 118 may be sized sothat the number of times that data array 122 is accessed may be reduced.Accordingly, by sizing first cache system 118 so that first cache system118 retains a quantity of data sufficient to satisfy a significantquantity of data requests (e.g., data request 20), the overallperformance of storage system 12 may be enhanced.

Further, second cache system 120 within data array 122 may be sized sothat the number of times that data tiers 102, 104, 106 are accessed maybe reduced. Accordingly, by sizing second cache system 120 so thatsecond cache system 120 retains a quantity of data sufficient to satisfya significant quantity of data requests (e.g., data request 20), theoverall performance of storage system 12 may be enhanced.

As discussed above, the instruction sets and subroutines of data cachingprocess 10, which may be stored on storage device 16 included withinstorage system 12, may be executed by one or more processors (not shown)and one or more memory architectures (not shown) included within storagesystem 12. Accordingly, in addition to being executed on servercomputer/controller 100, some or all of the instruction sets andsubroutines of data caching process 10 may be executed by one or moreprocessors (not shown) and one or more memory architectures (not shown)included within data array 122.

The Data Caching Process

As discussed above, data tiers 102, 104, 106 may be configured toprovide various levels of performance, wherein one or more of data tiers102, 104, 106 may be configured to be a lower performance data tier andone or more of data tiers 102, 104, 106 may be configured to be a higherperformance data tier.

Accordingly, data tier 102 may be configured as a higher performancedata tier and may include one or more flash storage devices. Data tier104 may be configured as a medium performance data tier and may includeone or more fiber channel storage devices. And data tier 106 may beconfigured as a lower performance data tier and may include one or morelower performance storage devices (e.g., SATA drives, SCSI drives, SASdrives, IDE drives, and EIDE drives).

Assume for illustrative purposes that data caching process 10 receivesread request 112 for content 110, which is a very old piece of contentstored within storage system 12. For example, assume that a customer ofa cellular provider contacts the cellular provider to obtain a copy of aphone bill (i.e., content 110) that is over two years old. Data cachingprocess 10 may process 200 read request 112 for content 110 storedwithin storage system 12.

Data caching process 10 may first determine whether content 110 ispresent within a front end cache system (e.g., first cache system 118).If so, data caching process 10 may obtain content 110 from first cachesystem 118 and provide the same to the requestor, thus satisfying readrequest 112. If data caching process 10 determines 202 that content 110is not present within the front end cache system (e.g., first cachesystem 118) of storage system 12, data caching process 10 may request204 content 110 from data array 122 (i.e., a multi-tiered data array),thus defining requested content 124.

Data array 122 may obtain requested content 124 from one of the datatiers (e.g., data tiers 102, 104, 106) included within data array 122and provide requested content 124 to data caching process 10. Data array122 may generate tier designator 126 that may define the specific datatier within data array 122 from which requested content 124 wasobtained. For example, since requested content 124 is quite old, it islikely that requested content 124 would be stored within a slower datatier. For illustrative purpose, assume that requested content 124 wasobtained from data tier 106, which would be identified in tierdesignator 126.

Data caching process 10 may receive 206 requested content 124 frommulti-tiered data array 122. Additionally, data caching process 10 mayalso receive 208 tier designator 126 (which concerns and is associatedwith requested content 124) that identifies the specific data tier(e.g., data tier 106) within data array 122 from which requested content124 was obtained.

Data caching process 10 may process 210 tier designator 126 to determinewhether requested content 124 should be written to the front end cachesystem (e.g., first cache system 118). Specifically, data cachingprocess 10 may write 212 requested content 124 to the front end cachesystem (e.g., first cache system 118) when requested content 124 wasobtained from slower data tiers within data array 122. Conversely, datacaching process 10 may not write 214 requested content 124 to the frontend cache system (e.g., first cache system 118) when requested content124 was obtained from faster data tiers within data array 122.

For example, assume that data caching process 10 is configure to storerequested content 124 only when requested content 124 is not from thefastest data tier (namely data tier 102). Therefore, upon receiving 206requested content 124 and receiving 208 tier designator 126, both frommulti-tiered data array 122, data caching process 10 may process 210tier designator 126. Accordingly, if requested content 124 is from datatier 106 or data tier 104, data caching process 10 may store 212requested content 124 within the front end cache system (e.g., firstcache system 118). Conversely. if requested content 124 is from datatier 102, data caching process 10 may not store 214 requested content124 within the front end cache system (e.g., first cache system 118).Since (in this example), requested content is quite old and was storedwithin the slowest data tier (i.e., data tier 106), data caching process10 may store 212 requested content 124 within the front end cache system(e.g., first cache system 118).

General

As will be appreciated by one skilled in the art, the present disclosuremay be embodied as a method, a system, or a computer program product.Accordingly, the present disclosure may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,the present disclosure may take the form of a computer program producton a computer-usable storage medium having computer-usable program codeembodied in the medium.

Any suitable computer usable or computer readable medium may beutilized. The computer-usable or computer-readable medium may be, forexample but not limited to, an electronic, magnetic, optical,electromagnetic, infrared, or semiconductor system, apparatus, device,or propagation medium. More specific examples (a non-exhaustive list) ofthe computer-readable medium may include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a transmission media such as those supportingthe Internet or an intranet, or a magnetic storage device. Thecomputer-usable or computer-readable medium may also be paper or anothersuitable medium upon which the program is printed, as the program can beelectronically captured, via, for instance, optical scanning of thepaper or other medium, then compiled, interpreted, or otherwiseprocessed in a suitable manner, if necessary, and then stored in acomputer memory. In the context of this document, a computer-usable orcomputer-readable medium may be any medium that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.The computer-usable medium may include a propagated data signal with thecomputer-usable program code embodied therewith, either in baseband oras part of a carrier wave. The computer usable program code may betransmitted using any appropriate medium, including but not limited tothe Internet, wireline, optical fiber cable, RF, etc.

Computer program code for carrying out operations of the presentdisclosure may be written in an object oriented programming languagesuch as Java, Smalltalk, C++ or the like. However, the computer programcode for carrying out operations of the present disclosure may also bewritten in conventional procedural programming languages, such as the“C” programming language or similar programming languages. The programcode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through a local area network/a widearea network/the Internet (e.g., network 14).

The present disclosure is described with reference to flowchartillustrations and/or block diagrams of methods, apparatus (systems) andcomputer program products according to embodiments of the disclosure. Itwill be understood that each block of the flowchart illustrations and/orblock diagrams, and combinations of blocks in the flowchartillustrations and/or block diagrams, may be implemented by computerprogram instructions. These computer program instructions may beprovided to a processor of a general purpose computer/special purposecomputer/other programmable data processing apparatus, such that theinstructions, which execute via the processor of the computer or otherprogrammable data processing apparatus, create means for implementingthe functions/acts specified in the flowchart and/or block diagram blockor blocks.

These computer program instructions may also be stored in acomputer-readable memory that may direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmableapparatus to produce a computer implemented process such that theinstructions which execute on the computer or other programmableapparatus provide steps for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

The flowcharts and block diagrams in the figures may illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustrations,and combinations of blocks in the block diagrams and/or flowchartillustrations, may be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

A number of implementations have been described. Having thus describedthe disclosure of the present application in detail and by reference toembodiments thereof, it will be apparent that modifications andvariations are possible without departing from the scope of thedisclosure defined in the appended claims.

What is claimed is:
 1. A computer-implemented method comprising:processing a read request for a piece of content stored within a storagesystem; determining that the piece of content is not present within afront end cache system of the storage system; requesting the piece ofcontent from a multi-tiered data array including at least two tieredstorage devices, thus defining requested content, wherein one of the atleast two tiered storage devices is a slower tiered storage device andone of the at least two tiered storage devices is a faster tieredstorage device; receiving the requested content from the multi-tiereddata array and generating an associated tier designator for therequested content; receiving the tier designator, concerning therequested content, that identifies a specific data tier within themulti-tiered data array from which the requested content was obtained,wherein the tier designator was generated at the multi-tiered data arrayand wherein the tier designator is configured to identify at least oneof a higher performance data tier, a medium performance data tier, and alower performance data tier; processing the tier designator to determinewhether the requested content should be written to the front end cachesystem, wherein the determination is based only upon the tierdesignator; writing the requested content to the front end cache systemwhen the tier designator indicates that the requested content isobtained from the slower tiered storage device within the multi-tiereddata array; and not writing the requested content to the front end cachesystem when the tier designator indicates that the requested content isobtained from the faster tiered storage device within the multi-tiereddata array.
 2. The computer-implemented method of claim 1 wherein themulti-tiered data array includes a faster data tier, a medium data tier,and a slower data tier.
 3. The computer-implemented method of claim 2wherein the faster data tier includes one or more flash storage devices,the medium data tier includes one or more fiber channel storage devices,and the slower data tier includes one or more SATA storage devices. 4.The computer-implemented method of claim 1 wherein the front end cachesystem is a flash-based front end cache system.
 5. Thecomputer-implemented method of claim 1 wherein the multi-tiered dataarray includes a back end cache system.
 6. A computer program productresiding on a non-transitory computer readable medium having a pluralityof instructions stored thereon which, when executed by a processor,cause the processor to perform operations comprising: processing a readrequest for a piece of content stored within a storage system;determining that the piece of content is not present within a front endcache system of the storage system; requesting the piece of content froma multi-tiered data array including at least two tiered storage devices,thus defining requested content, wherein one of the at least two tieredstorage devices is a slower tiered storage device and one of the atleast two tiered storage devices is a faster tiered storage device;receiving the requested content from the multi-tiered data array andgenerating an associated tier designator for the requested content;receiving the tier designator, concerning the requested content, thatidentifies a specific data tier within the multi-tiered data array fromwhich the requested content was obtained, wherein the tier designatorwas generated at the multi-tiered data array and wherein the tierdesignator is configured to identify at least one of a higherperformance data tier, a medium performance data tier, and a lowerperformance data tier; processing the tier designator to determinewhether the requested content should be written to the front end cachesystem, wherein the determination is based only upon the tierdesignator; writing the requested content to the front end cache systemwhen the tier designator indicates that the requested content isobtained from the slower tiered storage device within the multi-tiereddata array; and not writing the requested content to the front end cachesystem when the tier designator indicates that the requested content isobtained from the faster tiered storage device within the multi-tiereddata array.
 7. The computer program product of claim 6 wherein themulti-tiered data array includes a faster data tier, a medium data tier,and a slower data tier.
 8. The computer program product of claim 7wherein the faster data tier includes one or more flash storage devices,the medium data tier includes one or more fiber channel storage devices,and the slower data tier includes one or more SATA storage devices. 9.The computer program product of claim 6 wherein the front end cachesystem is a flash-based front end cache system.
 10. The computer programproduct of claim 6 wherein the multi-tiered data array includes a backend cache system.
 11. A computing system comprising: at least oneprocessor device; and at least one memory architecture coupled with theat least one processor device; wherein the at least one processor deviceis further configured to perform operations comprising; processing aread request for a piece of content stored within a storage system;determining that the piece of content is not present within a front endcache system of the storage system; requesting the piece of content froma multi-tiered data array including at least two tiered storage devices,thus defining requested content, wherein one of the at least two tieredstorage devices is a slower tiered storage device and one of the atleast two tiered storage devices is a faster tiered storage device;receiving the requested content from the multi-tiered data array andgenerating an associated tier designator for the requested content;receiving the tier designator, concerning the requested content, thatidentifies a specific data tier within the multi-tiered data array fromwhich the requested content was obtained, wherein the tier designatorwas generated at the multi-tiered data array and wherein the tierdesignator is configured to identify at least one of a higherperformance data tier, a medium performance data tier, and a lowerperformance data tier; processing the tier designator to determinewhether the requested content should be written to the front end cachesystem, wherein the determination is based only upon the tierdesignator; writing the requested content to the front end cache systemwhen the tier designator indicates that the requested content isobtained from the slower tiered storage device within the multi-tiereddata array; and not writing the requested content to the front end cachesystem when the tier designator indicates that the requested content isobtained from the faster tiered storage device within the multi-tiereddata array.
 12. The computing system of claim 11 wherein themulti-tiered data array includes a faster data tier, a medium data tier,and a slower data tier.
 13. The computing system of claim 12 wherein thefaster data tier includes one or more flash storage devices, the mediumdata tier includes one or more fiber channel storage devices, and theslower data tier includes one or more SATA storage devices.
 14. Thecomputing system of claim 11 wherein the front end cache system is aflash-based front end cache system.
 15. The computing system of claim 11wherein the multi-tiered data array includes a back end cache system.